[vtkusers] speed

[Jeff Baumes]

> Hi, I’m looking at a project modelling a large dataset in 3d. I looked at vpython briefly since I’m familiar with python but I found it far too slow for my purposes – a model composed of just 50,000 spheres ran like a dog on a mid range quadro card, and my models might go up to a million data points.
> So I’ve resigned myself to needing to use something like vtk in c++, however while I wait for it to compile in visual studio, I thought I might ask if even vtk can handle such a requirement? I need to be able to rotate and zoom around the models with reasonable ease as well as turn various components of the model on and off.

Actors are relatively heavy-weight objects that manage pipeline
connection, interaction, a mapper, etc. If you want 50,000 of
something, separate actors are likely not going to work. If you just
wanted a static set of spheres with no interactivity, I'd point you to
vtkGlyph3D, which would put all your spheres in one actor, but that is
probably not going to work for you either. What you need in this case
is probably to make a custom actor or mapper that manages the
rendering of all your spheres, that provides the functionality you
need but no more (e.g. do you need a separate pipeline input, mapper,
lookup table, etc. for each sphere?).

Jeff